Couple days ago, the low tire pressure came on in the front left of my tire. I thought I got a flat tire until I got outside, but it didn't look like it was flat. I thought it was the because of the loss of air whenever it gets cold outside.

I put air in it to 36 PSI, and the warning went off. The next morning, I start the car and I saw the damn warning again. There's no way in hell that it lost all the air that fast, so I checked it again with the air gauge in the gas station and it's down to 20 PSI.

Are you guys having the same problem? I'm tired of putting air in it every morning, and the tire felt like it didn't lose any air. I checked the tire if it also has something stuck on it, but there's none.

First check your tires for the proper tire pressure(s). I think your problem is that your car still has the old learned "target" pressure. The system is a dumb system... so it only knows what the last programed "target" was. When you add in more air pressure... the system will not know it.

THEN... with the car stopped(but the engine running), hold and reset the TPMS via the BC turn signal stalk or thru your iDrive menu. Then drive off when it says something like "resetting". It should only take a few hundred meters(if that!) of driving before the yellow light goes out.

IF you try resetting the TPMS while driving it will not reset. Ask me how I know this! lol

Also... if your tires ARE losing air pressure... a very common thing is the 11mm nut on the metal valve stems tend to loosen up. They only need to be snug! You can break them if you over torque the nuts. I think the specs is something like 4 Nm - very little torque!!

First check your tires for the proper tire pressure(s). I think your problem is that your car still has the old learned "target" pressure. The system is a dumb system... so it only knows what the last programed "target" was. When you add in more air pressure... the system will not know it.

THEN... with the car stopped(but the engine running), hold and reset the TPMS via the BC turn signal stalk or thru your iDrive menu. Then drive off when it says something like "resetting". It should only take a few hundred meters(if that!) of driving before the yellow light goes out.

IF you try resetting the TPMS while driving it will not reset. Ask me how I know this! lol

Also... if your tires ARE losing air pressure... a very common thing is the 11mm nut on the metal valve stems tend to loosen up. They only need to be snug! You can break them if you over torque the nuts. I think the specs is something like 4 Nm - very little torque!!

Yea... its a "dumb" TPMS system. You must reset the base target pressure so the TPMS computer knows what the pressure should be.

I think you will be fine now.

G.L.
Dackel

The low tire warning came on again, and had to fill more air for the 4th time this week. This is frustrating. I already scheduled a service for it so they can check it out. I'm not sure if I should try to tighten up the cap just like what everybody recommend, or just leave it up to the dealership?

Quote:

Originally Posted by b1aze

If you're down to 20psi by a manual gauge, you have a leak.

It kept on going to 20 psi by a manual gauge man, and how do I know exactly where the leak is? I've looked around the tires, and I don't see any nails or whatever. Any ideas?

Yea... its a "dumb" TPMS system. You must reset the base target pressure so the TPMS computer knows what the pressure should be.

I think you will be fine now.

G.L.
Dackel

The low tire warning came on again, and had to fill more air for the 4th time this week. This is frustrating. I already scheduled a service for it so they can check it out. I'm not sure if I should try to tighten up the cap just like what everybody recommend, or just leave it up to the dealership?

Quote:

Originally Posted by b1aze

If you're down to 20psi by a manual gauge, you have a leak.

It kept on going to 20 psi by a manual gauge man, and how do I know exactly where the leak is? I've looked around the tires, and I don't see any nails or whatever. Any ideas?

Soapy water with the wheel off is a start. Spray everything down and watch for bubbles. Check the torque on the TPMS nuts also.